He said the DOH has sent a team to Batanes to track how mosquitoes had bred in the province, which he said used to average only two dengue cases a year.

Tayag said they are not discounting the possibility that tourists who had dengue may have spread the disease.

“So many tourists visit the site because of its beauty. It is possible some of them may have had a part in spreading dengue. We will send a team to the province to trace where the dengue-carrying mosquitoes bred)," he said.

Last weekend, Sabtang town in Batanes was placed under a state of calamity due to the number of dengue cases in the area in the last two weeks."